Method of improving the adhesion of rubber to cotton



.amine to 100 parts of shellac).

Patented Sept. 16, 1941 UNITED- STATES PATENT OFFICE METHOD OF HHPROVINGTHE ADHESION OF RUBBER T COTTON Richard A. Crawford, Akron, Ohio,assignor to p The B. F. Goodrich Company, New York, N. Y.,

a corporation of New York No Drawing. Application August 17, 1939,Serial No. 290,625

Claims.

v This invention relates to the adhesion-of rubber to cotton in the formof cords, fabrics, and the like.

The length of service of many articles of commerce embodying cotton andrubber such as tires and belts, for instance, is largely dependent uponthe degree of adhesion between the rubber and the cotton. It is theprincipal object of this invention, accordingly, to provide a methodwhereby the adhesion between the rubber andthe cotton may be increased.

The method of this invention comprises the application of ashellac-amine soap to cotton prior to associating the cotton with rubberand vulcanizing the composite product. Shellacamine soaps are awell-known class of compounds prepared by the saponification of shellacwith amines such as methyl amine, ethyl amine, dimethyl amine, trimethylamine, triethanol amine, ethylene diamine, triethylene tetramine,cyclohexyl amine, piperidine, morpholine, etc., the soaps prepared fromstrongly basic amines such as the alkyl amines being preferred.

The shellac-amine soap may be applied directly to the cotton if desired.This method, however,

. may produce unnecessarily thick coatings on the cotton, so it isordinarily preferred to deposit the soap upon the cotton from solution.The shellacamine soap is usually added in a rather volatile solvent suchasalcohol to aid in the drying of the cord, although aqueous solutionsmay be em ployed if desired. The soap may be applied to the cottonfibers by any desired means, although dipping the cotton in thedispersion is the method now preferred. The cotton is then dried priorto association with unvulcanized rubber.

In case the cotton is in the form of cords, the

treated cords may be dried under tension in the manners well known tothe art. 7

As a specific embodiment of this invention,

, square woven cotton fabric was dipped in a 10% alcoholic solution of asoap prepared by the saponiflcation of equivalent amounts of diethylamine and shellac (7.27 parts by weight of diethyl The treated fabricwas dried and coated with a tire carcass stock. Two plies weresuperposed and vulcanized under pressure in a heated mold together withsimilar structures made from untreated fabric.

When it was attempted to separate the plies,

it was found that a 35% improvement in adhesion was obtained by treatingthe fabric with the shellac-amine soap;

, the treatment of this invention, but it has been found by tests ontires containing the treated cords of this invention that thetemperatures developed in the tires during operation is greatly reduced.ton cords of this invention accordingly last longer and run with lessdanger of blowing out than ordinary tires.

Although I have herein disclosed specific examples of the method of myinvention, I do not intend that the invention be limited solely thereto,for it will be ,obvious to those. skilled in the art that manymodifications are the spirit and scope of the invention as defined inthe appended claims.

I claim:

' -1. The method of improving the adhesion of rubber to cotton whichcomprises applying to the cotton a shellac-amine soap, associating thetreated cotton with vulcanizable rubber, andvulcanizing the assemblage.

2. The method of improving the adhesion of rubber to cotton cord whichcomprises applying to the cord a solution of a shellac-a'nine soap,

drying the cord, associating the treated cord with vulcanizable rubber,and vulcanizing the assemblage.

3-. In a method of adhering rubber to cotton,

.' the step which consists of applying a shellac-.

amine soap to the cotton prior to association with the rubber.

.4. The method of claim 1 in which the shellacamine soap is preparedfrom shellac and an alkyl amine.

5. An article of manufacture comprising cotton containing ashellac-amine soap and a layerof I vulcanized rubber adhered to thecotton.

momma A. ca-awroan.

The tires containing the treated cot-'

